A magnetic multipole reactor for high-flux reactive-ion etching

A 13.56-MHz rf discharge has been combined with two kinds of magnetic field. A multipole field, generated by permanent magnets in the surrounding walls, is used to confine the plasma. Superimposed on this is a variable magnetic field parallel to the substrate surface, which is shown to give a considerable increase in plasma density and reduction of electrode self-bias. Etch rates of SiO2 in a CF4 discharge of 5000 Å/min at mTorr pressures are presented.